Radio Frequency Identification (RFID) technology is the use of radio frequency waves (RF) to exchange information for identification purposes. A RFID system typically includes a RFID reader or transceiver having an antenna and a RFID tag or transponder containing unique information. The antenna of the RFID reader emits RF signals to activate any RFID tags within a reading range. The RFID tag, when within the vicinity of the RF signal, is activated by the RF signal from the RFID reader. This allows the RFID reader to reads the unique information in the RFID tag.
RFID technology has been widely used for tracking and monitoring products, for example, for inventory control in a warehouse. In inventory control system, a RFID tag containing a unique code is attached to each item in the warehouse. This allows each item in the warehouse to be uniquely identified by the unique code of the attached RFID tag. One or more RFID readers are installed at predefined locations to read the RFID tags attached to the items in the warehouse. By keeping track of all the unique codes read by the RFID readers, a person such as the warehouse owner would have an accurate knowledge of the inventory level. Accordingly, any discrepancy between inventory record and physical inventory is eliminated. The use of RFID technology in inventory control system also reduces any source of human errors which may arise in manual stock taking processes.
For any large scale deployment of RFID technology for inventory control system, the positioning of the RFID readers in the warehouse is crucial. Any brute force approach of positioning the RFID readers in the warehouse can lead to blind-spots in the RFID signal coverage or interferences between the RFID readers. Insufficient RFID readers in the warehouse may result in less than 100% area coverage of the RFID Reader signals, resulting in blind-spots. Accordingly, any RFID tags, and hence items, in one of the blind-spots will not be read by the RFID reader. However, if the RFID readers are spaced too closely together, interference among the RFID readers reduces the reliability and efficiency of the RFID system.
Accordingly, it is desirable to have a method to determine optimal positioning of the RFID readers in a warehouse that results in 100% coverage but yet do not have interferences among the RFID readers.